For me the convenience factor has to do with the fact that I can vacuum seal and freeze a bunch of meat at once, then it's just a matter of tossing the vacuum sealed bag in the circulator a few hours before dinner. Then I just need to pull it out, hit it with the torch, and we're ready to eat. I suspect the longer cooking time to account for the meant being frozen helps with fat rendering.

We buy half a beef every six months or so (split with my parents, so I guess it's technically 5/7th's of a half? 5/14th's of a cow?). For a few hours on a weekend doing some prep/portioning, I can dramatically reduce the workload for several week's worth of meals.

Obviously there's other tradeoffs involved and different personal circumstances to consider, but for me the circulator wins out from a convenience perspective.

Likewise, I’m 100% not against a pure reverse sear. I just prefer to focus on getting the sides prepped and done, knowing that whenever they’re ready, the meat’s only a few minutes out.